Montana became a United States possession with the Louisiana Purchase in 1803 and was organized as a territory in 1864. It became the 41st state in the union on November 8, 1889 and covers an area of 147,138 square miles, making it the fourth largest in the country.
The west end of the state is covered by the rugged and forested peaks of the Rocky Mountains. The "Big Sky" country of the Great Plains covers the eastern two thirds of the state. Montana has one national park, Glacier National Park, located just under the Canadian Border, and also the northern edge of Yellowstone National Park lies on the southern border of the state. Vast areas of national forest cover much of the state.
For More Information:
See Wikipedia's Montana page.